Some patients require repeated injections of a medication via an intravenous catheter. In such cases, it is common to insert a catheter prior to a first injection and then maintain the catheter within the patient's vasculature for use during subsequent injections. After a medication is administered through the catheter, the catheter is typically flushed with a saline solution to clear out any remaining medication and to maintain the catheter sterile. Also, to prevent clotting of blood within the catheter, the catheter is oftentimes flushed with an anticoagulant solution such as heparin.
In such scenarios, the medication, and possibly the saline solution and/or heparin (hereinafter collectively referred to as “solutions”), oftentimes must be injected at a specified rate. To facilitate injecting the solutions at the appropriate rate, injection pumps are used. An injection pump is a device that causes a solution to be injected into a patient's vasculature in accordance with a desired rate.
Some injection pumps, such as the Freedom60® infusion pump manufactured by RMS Medical Products which is shown in FIG. 5, are designed to receive a single syringe to which the patient's catheter is connected via tubing. These syringe-based injection pumps are commonly used for in-home injections. Such injection pumps are configured to apply a constant force to the syringe's plunger thereby causing the solution to continuously flow out from the syringe and into the tubing. To control the flow rate of the solution, tubing of an appropriate size can be selected.
One problem that exists with these syringe-based injection pumps is that, when solutions from multiple syringes must be injected, the administrator of the solutions must perform the injection process for each syringe. For example, if the patient required the sequential injection of a medication, a saline solution, and heparin, the administrator would first have to load the medication syringe into the injection pump, connect the medication syringe to the catheter, and start the injection process. Then, once the injection pump had fully dispensed the medication, the administrator would have to disconnect the medication syringe from the catheter and attach the saline syringe to separately administer the saline solution (which is typically performed directly without an infusion pump but could also be done using an infusion pump if desired). Finally, after the saline solution is administered, the administrator would have to disconnect the saline syringe from the catheter and connect the heparin syringe to inject the heparin (which is also typically performed directly without an infusion pump but could also be done using an infusion pump). This process can require a substantial amount of time especially if the required injection rate of the medication is slow.
In these situations, if the administrator was not able to switch out the syringe to initiate the next stage of the injection (e.g., if the administrator fell asleep while administering the solutions at night), the catheter could become unusable without further action. For example, if the saline solution and heparin are not injected, clotting may occur within the catheter that prevents further injections through the catheter. In such cases, the catheter may have to be replaced which typically requires visiting the hospital or other medical facility. Even if the clotting is minimal or if no clotting occurs, without proper flushing, the catheter may become contaminated thereby increasing the risk of infection or discomfort to the patient.